Based on a European union request, the International Council for the Exploration of the Sea (ICES) has explored and advised on indicators of pressure and impact of bottom trawling on the seabed, and of trade-offs in the catch and value of landings. Such assessment frameworks combine pressure (trawling intensity) with benthic habitats and their sensitivity to estimate the impacts on regional scale. The main differences between the indicators lay in their underlying scientific basis for determining sensitivity. Two approaches, the longevity and the population dynamic approach, are based on a statistical prediction of the longevity distribution of the benthic community, which is a practically very attractive way to capture sensitivity to trawling. The BH3 approach uses a categorical scoring approach for sensitivity. The BH2 relies on empirical observations to estimate changes in Margaleff diversity. In general, the use of continuous environmental variables, rather than the EUNIS habitat classes seemed promising for assessing impacts as they result in larger gradients in the sensitivity layer. Major steps forward in assessing the impact of bottom trawling were made, but improved parameterization and further ground-truthing is required, which will be further taken up in the ICES working group WGFBIT.
The Water Framework Directive (WFD; 2000/60/EG) aims to achieve a good ecological and chemical quality status of the European waters (Rivers, Lakes, coastal- and transitional waters). The quality status is determined based on the evaluation of different quality elements, e.g. macro-invertebrates. Macro-invertebrates are good indicators for detecting anthropogenic impacts and ecological degradation. The Belgian Coastal water body (< 1 nautical mile) is a small area, but this environment is highly influenced by the inputs from 4 harbors and 2 rivers (Ijzer, Scheldt), coastal defense works (dredging, sand suppletion) and fisheries. To evaluate the ecological quality status of this area, a WFD monitoring program was implemented in 2007 and the BEQI (Benthic Ecosystem Quality Index) (www.beqi.eu) is used as macro-invertebrate indicator tool. The ecological quality status has to be reported in the River Basin Management Plan of a water body, which is characterised by a reporting cycle of six years (2009-2015). The current WFD monitoring program for macro-invertebrates is designed to evaluate its ecological quality status with a good confidence on an adequate spatial and temporal scale. A good spatial coverage of the samples per habitat in a water body is very important for a water basin assessment (habitat approach), due to the small scale spatial variation of the benthic characteristics. Therefore, samples were randomly taken at 9 or 11 locations, representative for one or more habitat types ( Abra alba, Nephtys cirrosa and Macoma balthica habitat), in the water body Belgian Coast. A temporal coverage of the samples is important due to the fact that the benthic characteristics show strong year-to-year variations. Therefore, a yearly monitoring is executed instead of monitoring once over the evaluation period of 6 years. Currently, we are halfway of the first monitoring cycle (2007-2012). Finally to obtain a good confidence, a high number of samples has to be taken to reduce the chance of misclassification in the ecological quality status. Therefore, the number of samples is determined based on the observed variance in benthic characteristics in the reference dataset of each habitat type. In this report, the monitoring results of the third year (2009) are outlined, together with an ecological quality status evaluation over the first part (2007-2009) of the first monitoring cycle. Beside it, a profound analysis on the habitat approach and a confidence analysis of the assessment of the macro-invertebrate monitoring program is made. The most obvious pattern in the benthic data of the year 2009 is the massive recruitment of the bivalve Ensis directus , an invasive alien species, along the entire coastline. The linking of the samples to a certain habitat type is less obvious than in the previous years, partly due to the presence of Ensis directus. There are also more samples taken in sandy sediments ( Nephtys cirrosa habitat). The BEQI level 3 shows that the Abra alba and Nephtys cirrosa habitat are in moderate status compared to the reference situation, which is mainly due to Ensis directus and a lower species richness. The Macoma balthica habitat is in a good status, mainly due to the high status of the parameter density. The ecological quality status assessment over the period 2007-2009 shows an overall moderate status of the water body Belgian Coast for the quality element macro-invertebrates, due to the moderate status of all habitats. The Abra alba habitat shows a moderate status for most parameters, due to lower densities compared to the reference situation, mainly of the species Spisula subtruncata, Magelona johnstoni and Lanice conchilega . The poor to moderate status of the habitat. Nephtys cirrosa is due to the unusual high benthic densities ( Ensis directus ) in this sandy environment. The Macoma balthica habitat at the west coast is in a good status, but moderate in the central and eastern coast. This moderate status is mainly due to the nearly absence of Petricola pholadiformis, Barnea candida and Polydora spp. The number of species expected in this habitat type is also lower compared to the reference situation. It seems that the moderate benthic status of the Belgian Coastal waters is mainly caused by the lower densities and presence of certain key species in each habitat or the introduction and success of an alien species ( Ensis directus ). This ecological degradation of the macro-invertebrate fauna in the Belgian coastal area cannot directly be linked to one anthropogenic pressure, but is probably the result of the combined acting of the present anthropogenic impacts. Two aspects, which are of importance in the benthic monitoring design, are the habitat approach and the confidence analysis on the assessment and this is investigated in more detail in this report. Currently, the determination of the habitat type of each sample is based on a biological analysis of the data, funded with sedimentological sample information. This approach may lead to the assignation of some poor benthic samples, qua diversity and density, to the wrong benthic habitat type. In other words, this approach can mask the real habitat potential of some locations. Secondly, the assigned habitat type of some parts of the locations does not correspond with the habitat suitability map. Therefore, it can be advisable to re-run the habitat suitability model in the Belgian Coastal area, based on the recent gathered monitoring information. A different procedure for habitat assignation of the samples has an effect on the EQR score's of the habitat, as tested in this report. Therefore, we concluded that one approach has to be selected, based on the visions of the benthic experts in Belgium. The confidence of the ecological quality assessment, coupled to the sampling effort, is judged with a statistical power analysis in the BEQI approach. An estimate of the sampling effort depends on the wanted power, the effect size and the variance in the benthic habitat characteristics (number of species, density). Currently, confidence classes are defined based on the effect size that can be measured with a power of 75%. Setting the power on 75% should lead to an acceptable sample effort. For obtaining a good confidence, the sampling effort in the assessed habitat has to be of that size to detect an effect size of factor 2 (halving or double) with a power of 75%. Due to difference in variance in benthic parameters, the sampling effort needs to be much higher for the parameter density compared to number of species and varies also between the three habitat types. By this kind of analysis, the government and scientists can investigate the sampling effort to obtain a certain confidence over the effect size they want to judge. There can be concluded that, regarding the quality element macro-invertebrates, the ecological status assessment over the period 2007-2009 assigns the Belgian coast as moderate. Therefore, the operational monitoring program needs to be continued. Adaptations or reductions in the program are possible, whereof some suggestions were tested and reported in this report, but the aspects regarding the habitat approach and confidence may not be neglected.
Bioturbation, the biogenic modification of sediments through particle reworking and burrow ventilation, is a key mediator of many important geochemical processes in marine systems. In situ quantification of bioturbation can be achieved in a myriad of ways, requiring expert knowledge, technology, and resources not always available, and not feasible in some settings. Where dedicated research programmes do not exist, a practical alternative is the adoption of a trait-based approach to estimate community bioturbation potential (BP c ). This index can be calculated from inventories of species, abundance and biomass data (routinely available for many systems), and a functional classification of organism traits associated with sediment mixing (less available). Presently, however, there is no agreed standard categorization for the reworking mode and mobility of benthic species. Based on information from the literature and expert opinion, we provide a functional classification for 1033 benthic invertebrate species from the northwest European continental shelf, as a tool to enable the standardized calculation of BP c in the region. Future uses of this classification table will increase the comparability and utility of large-scale assessments of ecosystem processes and functioning influenced by bioturbation (e.g., to support legislation). The key strengths, assumptions, and limitations of BP c as a metric are critically reviewed, offering guidelines for its calculation and application.
Imagine a future where dynamically, from year to year, we can track the progression of alien species (AS), identify emerging problem species, assess their current and future risk and timely inform policy in a seamless data-driven workflow. One that is built on open science and open data infrastructures. By using international biodiversity standards and facilities, we would ensure interoperability, repeatability and sustainability. This would make the process adaptable to future requirements in an evolving AS policy landscape both locally and internationally. In recent years, Belgium has developed decision support tools to inform invasive alien species (IAS) policy, including information systems, early warning initiatives and risk assessment protocols. However, the current workflows from biodiversity observations to IAS science and policy are slow, not easily repeatable, and their scope is often taxonomically, spatially and temporally limited. This is mainly caused by the diversity of actors involved and the closed, fragmented nature of the sources of these biodiversity data, which leads to considerable knowledge gaps for IAS research and policy. We will leverage expertise and knowledge from nine former and current BELSPO projects and initiatives: Alien Alert, Invaxen, Diars, INPLANBEL, Alien Impact, Ensis, CORDEX.be, Speedy and the Belgian Biodiversity Platform. The project will be built on two components: 1) The establishment of a data mobilization framework for AS data from diverse data sources and 2) the development of data-driven procedures for risk evaluation based on risk modelling, risk mapping and risk assessment. We will use facilities from the Global Biodiversity Information Facility (GBIF), standards from the Biodiversity Information Standards organization (TDWG) and expertise from Lifewatch to create and facilitate a systematic workflow. Alien species data will be gathered from a large set of regional, national and international initiatives, including citizen science with a wide taxonomic scope from marine, terrestrial and freshwater environments. Observation data will be funnelled in repeatable ways to GBIF. In parallel, a Belgian checklist of AS will be established, benefiting from various taxonomic and project-based checklists foreseen for GBIF publication. The combination of the observation data and the checklist will feed indicators for the identification of emerging species; their level of invasion in Belgium; changes in their invasion status and the identification of areas and species of concern that could be impacted upon by bioinvasions. Data-driven risk evaluation of identified emerging species will be supported by niche and climate modelling and consequent risk mapping using critical climatic variables for the current and projected future climate periods at high resolution. The resulting risk maps will complement risk assessments performed with the recently developed Harmonia+ protocol to assess risks posed by emergent species to biodiversity and human, plant, and animal health. The use of open data will ensure that interested stakeholders in Belgium and abroad can make use of the information we generate. The open science ensures everyone is free to adopt and adapt the workflow for different scenarios and regions. The checklist will be used at national level, but will also serve as the Belgian reference for international databases (IUCN - GRIIS, EASIN) and impact assessments (IPBES, SEBI). The workflow will be showcased through GEO BON, the Invasivesnet network and the COST Actions Alien Challenge and ParrotNet. The observations and outcomes of risk evaluations will be used to provide science-based support for the implementation of IAS policies at the regional, federal and EU levels. The publication of Belgian data and checklists on IAS is particularly timely in light of the currently ongoing EU IAS Regulation and its implementation in Belgium. By proving that automated workflows can provide rapid and repeatable production of information, we will open up this technology for other conservation assessments.
